In collaboration with the Louisiana State University Medical Center, a population based case-control interview study of newly diagnosed histologically confirmed CNS neuroglial tumors among adults aged 20-79 years will be conducted in the six county Texas Gulf Coast Area and twenty-six parishes in southern Louisiana. Cases of CNS neuroglial tumors diagnosed during the interval July 1979 to June 1984 will be ascertained through existing systems of case ascertainment in the two study areas (Texas and Louisiana). An estimated 954 cases of neuroglial tumors will be identified and all available tissue specimens will be reviewed by collaborating neuropathologists in the two study areas. A population based comparison group, matched on age, race and sex, will be selected in the two study areas. Detailed personal interviews with case and comparison subjects will be conducted to ascertain occupational, residential, radiological and familial exposures and to estimate the relative risk of neuroglial tumors associated with these risk factors. In the event of death or disability, interviews will be conducted with next of kin. Incidence rates for neuroglial tumors for the interval July 1979-June 1984 will be estimated and compared for the two study areas and for specific Texas counties and Louisiana parishes. A detailed occupational and industrial coding scheme will be used to facilitate identification of high risk occupations and industries in the two study areas. Interview data from the two study areas will be analyzed separately and combined, as indicated by initial analyses. Data regarding familial aggregation will be validated by use of mailed questionnaires, death certificates and hospital records.